Recently, various electronic devices such as a digital camera and a mobile phone have been increasingly equipped with a memory card socket structure for allowing a small-sized storage medium (hereinafter, simply referred to as a ‘memory card’) such as a Mini SD Memory Card (Registered Trademark) to be inserted thereinto or taken out therefrom.
As one type of such conventional memory card socket structures, there has been proposed one equipped with a memory card detecting mechanism for detecting whether a memory card is inserted or not (see, for example, Japanese Patent Laid-open Application No. 2004-349223: Reference 1).
The memory card socket structure disclosed in Reference 1 has a movable spring piece which is configured to be in pressurized contact with a stationary contact as a memory card is inserted into the socket structure. As a result of the movable spring piece being connected with or disconnected from the stationary contact, a circuit is opened or closed, whereby the presence or absence of the memory card in the socket structure is detected electrically. The movable spring piece is configured so as to be moved along a width-wise direction of the memory card while coming into contact with a lateral side (width-wise end surface) of the memory card.
In this way, when a memory card is in a size similar to the Mini SD Memory card, it is relatively easy to configure a movable spring piece to provide an enough biasing force (contact separation force) to play its intended role. However, in case of a memory card socket structure adapted for smaller memory cards, the movable spring piece is required to be reduced in size, which in turn, causes difficulty of exerting a sufficient biasing force with such movable spring pieces.
Further, in the configuration where the movable spring piece is moved along the width-wise direction of the memory card, as illustrated in Reference 1, a stroke of the movable spring piece needs to be set greater than a force required for a dimensional tolerance of the memory card in its width-wise direction. However, as for a memory card socket structure adapted for a memory card of a smaller size, the size of a movable spring piece employed therein should be smaller as well, thereby causing a difficulty of setting the stroke to be greater than the force required for the dimensional tolerance.